Many animals have a diffuse extra-ocular sensitivity to light. Limited areas of particular dermal photosensitivity have been localized in, for example, Mya siphon (Light, 1930) and the tail of ammocoetes (Steven, 1951) but identification of the receptors is difficult. Even when candidate receptors are known, owing to their small size and the limitations of light microscopy, they have been imperfectly characterized (e.g. Light, 1930) and their identification questioned (Steven, 1963).

A fungus, most probably allied to the Saprolegniacese, has been found infecting Pinnotheres. Pea-crabs so infected always die, but there is not as yet sufficient evidence to determine whether the fungus is pathogenic or only invades tissue which has been destroyed by parasitic bacteria. Although having the general characters of the family it apparently differs from all members so far described in that it occurs in a marine invertebrate and is almost entirely internal in habit, the zoosporangia occurring within the tissue of the host.

Lacuna vincta appeared at Musquash Head, New Brunswick, in large numbers from June to August 1981 principally on lower midlittoral and infralittoral fringe Fucus edentatus. The population reached a mean maximum of 280/m2 in June; by mid September the animals had disappeared. The L. vincta grazed heavily and deposited egg masses on Fucus edentatus but little on other species. All fine and filamentous and encrusting algal species and rock were avoided for egg deposition. Egg mass abundance peaked with the population in June with a mean of 180/m2. Mean egg production in June was 83000/m2.

Both snail and egg mass distributions were correlated with the percentage cover of F. edentatus, reaching a maximum at 40–75 cm above mean low tide level.

The snails ranged in length from 2–7 mm, consisting of three cohorts from different larval settlements. Growth was rapid in July averaging 0·6 mm/month slowing later.

The food plant Fucus edentatus showed a heavy impact of the herbivore. Weight reductions attributable to grazing rose from 56 % in June to 79 % in August and grazed plants tended to thicken rather than elongate with growth. Grazing removed about 79 % of the net production of F. edentatus which averaged 61 g dry wt/m2/day. The impact of the L. vincta population on F. edentatus seems extraordinarily severe.

Studies on the quantitative distribution of cephalopods in the Arctic are limited, and almost completely absent for the Barents Sea. It is known that the most abundant cephalopods in the Arctic are Rossia palpebrosa and Gonatus fabricii. Their biomass and abundance have been assessed for the first time in the Barents Sea and adjacent waters. The maximum biomass of R. palpebrosa in the Barents Sea was 6.216–6.454 thousand tonnes with an abundance of 521.5 million specimens. Increased densities of biomass were annually registered in the north-eastern parts of the Barents Sea. The maximum biomass of G. fabricii in the Barents Sea was 24.797 thousand tonnes with an abundance of 1.705 billion specimens. The areas with increased density of biomass (higher than 100 kg km−2) and abundance (more than 10,000 specimens km−2) were concentrated in deep-water troughs in the marginal parts of the Barents Sea and in adjacent deep-water areas. The biomass and abundance of R. palpebrosa and G. fabricii in the Barents Sea were much lower than those of major taxa of invertebrates and fish and than those of cephalopods in other parts of the World Ocean. It has been suggested that the importance of cephalopods in the Arctic ecosystems, at least in terms of quantitative distribution, could be somewhat lower than in the Antarctic or the tropics. Despite the impact of ongoing warming of the Arctic on the distribution of cephalopods being described repeatedly already, no impact of the current year's climate on the studied species was found. The only exception was the abundance of R. palpebrosa, which correlated with the current year's climate conditions.

Elasmobranchs, unlike teleosts, do not possess otoliths or scales suitable for age determination. Various skeletal structures of elasmobranchs have been used in an attempt to find a reliable ageing technique. These include the centra of Raja fusca (Ishiyama, 1951). R. eglanteria (Daiber, 1960), R. erinacea (Richards, Merriman & Calhoun, 1963) and Cetorhinus maximus (Parker & Stott, 1965). Yokota (1951, 1952) has described annual growth increments on the claspers of various elasmobranch species. Stevens (1975) made vertebral ring counts in the blue shark, Prionace glauca L. More recently Jones & Geen (1977a,b), using X-ray spectrometric analysis, have examined the vertebral circuli of dogfish found in British Columbia waters. Methods of age determination, using the spines of the spurdog (Squalus acanthias L.) have been described by Kaganovskaia (1933, 1937), Bonham et al. (1949) and Aasen (1961). All these authors assumed that the more or less regular series of dark bands or ‘rings’, extending from a white pigment-free base of the enamel to near the tip, were annual. Holden & Meadows (1962), on the basis of the internal and external features of the spines, concluded that the dark bands did represent annual growth increments. In particular, they argued that the dark bands were laid down during the winter when growth would be slowest, whereas the faster growth in the summer was represented by the light bands. Holden & Meadows (1962) identified several conditions, e.g. birth, double, false and spawning rings – that made interpretation of the ring structure and subsequent age determination difficult.

Three species of the callianassid genus Nihonotrypaea occur in the Ariake Sound estuarine system, southern Japan; they consist of two tidal-flat species (N. harmandi; N. japonica) and one boulder-beach species (N. petalura), with maximum population densities of 1440, 343, and 12 ind m−2, respectively. Nihonotrypaea harmandi and N. petalura are distributed along the coastline from the outermost part of the sound to the open sea, while N. japonica occurs in the middle part of the sound. Nihonotrypaea japonica has an extended reproductive period from late winter to autumn, while those of the other species are from late spring or summer to autumn. Interspecific comparisons were made for recently laid egg size (as volume) and clutch size (as number of eggs per female). Only in N. japonica was a seasonal egg size variation observed, being significantly larger in winter to spring (mean=0.106 mm3) than in summer (0.080 mm3). By contrast, clutch size was significantly smaller in winter to spring, resulting in nearly the same clutch volume per female (product of the mean egg volume and clutch size) between the seasons. Among the three species, the egg size was ordered as N. japonica (overall mean volume through the seasons=0.092 mm3)>>N. petalura (0.057 mm3)>N. harmandi (0.054 mm3). The clutch size was ordered as N. harmandi>N. petalura≈N. japonica. The clutch volume was ordered as N. japonica≈N. harmandi>N. petalura. The smallest clutch volume value for N. petalura female showed an opposite trend to the relative size of the major cheliped found in a previous study.

Heavy metals, as well as affecting the growth rate and photosynthesis of algae, have a considerable effect on the size and morphology of algal cells (see, for example, Erickson, 1972; Nuzzi, 1972; Davies, 1974; Kayser, 1976). Changes in the colour of algae in the presence of heavy metals have also been observed (Greenfield, 1942). At metal concentrations resulting in total growth inhibition of algae the cells, although abnormal, are not necessarily dead (see, for example, Nielsen & Kamp-Nielsen, 1970; Erickson, 1972; Nuzzi, 1972; Blankenship & Wilbur, 1975).

In heavy-metal toxicity studies with Ditylum brightwellii (West) Grunow (Canterford & Canterford, 1979) it was observed that low concentrations of ethylenediaminetetraacetic acid (EDTA) and toxic concentrations of several heavy metals resulted in the formation of abnormal cells. In the present paper factors affecting the formation of abnormal cells are discussed. Experiments were carried out to establish whether or not these abnormal cells could be regenerated.

The intent of this work is to summarize the available knowledge on the appearance, identification and distribution of Cuvier's beaked whales (Ziphius cavirostris) in the Adriatic Sea through a review of historical data, inspection of natural history collections and collection of original data. In total, eleven occurrences are documented of Cuvier's beaked whale along the Adriatic coast with all records originating from the deep southern Adriatic basin. The number of recorded stranded Cuvier's beaked whales in the southern Adriatic represents about 3% of the recorded specimens in the entire Mediterranean. This percentage increases up to about 5% when considering only data collected after the first recorded stranding of the recent era in 1975. Comparing these percentages to the extent of the area relative to the Mediterranean, the proportion of occurrence of the total stranded Cuvier's beaked whales in the southern Adriatic ranged between the same to double of that of the entire Mediterranean Sea. Therefore, the southern Adriatic Sea should be considered as a potentially relevant habitat of the Cuvier's beaked whale. This hypothesis has clear conservation implications particularly in view of the adverse impact of sonar experiments, carried out by navies from several countries, on this species and should be further investigated. Finally, there is no evidence of the northern bottlenose whale (Hyperoodon ampullatus) ever having occurred in this part of the Mediterranean region.

Regular sea temperature measurements have been made since 1975 at Gravelines (French coast of the Southern Bight of the North Sea) within the framework of a research programme aimed at monitoring the influence of the thermal discharge of a nuclear power plant. The sampling has yielded a 28-year time-series. Pluriannual natural fluctuations of temperature show cyclic patterns and long-term trends in good accordance with global climatic changes as revealed by the NAO (North Atlantic Oscillation) annual index.

The genital products of Saccoglossus horsti are discharged within the burrows and expelled after the tide has ebbed. They are not retained in the burrows for any length of time.

Fertilization occurs mainly in the overlying surface water, or during the flood.

An ‘epidemic’ spawning was observed on three occasions in the field.

A rise of temperature to about 160° C. is regarded as the essential factor primarily responsible for initiating the spawning.

The females were observed to spawn before the males. Some reciprocal inducement might have occurred.

The breeding season in the Solent area is mainly confined to the months of May, June and July, and is seemingly dependent on climatic and tidal conditions during these months.

The spawning behaviour of other species of the Enteropneusta is discussed.

Benthic habitat composition is a key factor that structures assemblages of coral reef fishes. However, natural and anthropogenic induced disturbances impact this relationship. This study investigates the link between benthic habitat composition and fish functional groups in four countries in the Western Indian Ocean (WIO). Benthic composition of 32 sites was quantified visually from percentage cover of hard and soft corals, rubble, turf, fleshy and crustose coralline algae. At each site, abundance of 12 coral-associated fish functional groups in 50 × 5 m transects was determined. Cluster analysis characterized reefs based on benthic cover and revealed five habitat types (A, B, C, D and E) typified by decreasing cover of hard corals, increasing cover of turf and/or fleshy algae and differences in benthic diversity. Habitat type A was present in all four countries. Other habitats types showed geographic affiliations: notably Comoros sites clustered in either habitats B or E, northern Madagascar had B, C and D type habitats, whereas sites in central Tanzania and northern Mozambique had habitats D and E. Fish functional groups showed significant linkages with some habitat types. The abundances of corallivores, invertivores, detritivores and grazers were higher in habitat B, whereas planktivores and small excavators showed lower abundances in the same habitat. These linkages between benthic habitat types and fish functional groups are important in informing priority reefs that require conservation and management planning.

The study aims to provide the first detailed account of the diversity and composition of the community associated with biogenic reefs formed by serpulid worms. Ten reefs (aggregations of calcareous Serpula vermicularis tubes), spanning a broad size-range, were collected from Loch Creran, Scotland, a Special Area of Conservation designated principally for the protection of its biogenic reefs. Total faunal abundance was strongly linearly related to reef weight, whilst taxon richness exhibited a hyperbolic relationship with reef size. 278 taxa were recorded from the ten reefs, with a reef of 0.1 m2 area supporting 163 taxa and 12756 individuals, which appears to represent considerable augmentation of diversity and abundance for sedimentary areas of the loch where the reefs occur. The reef assemblage was dominated by polychaetes (94 taxa), molluscs (70 taxa) and crustaceans (45 taxa). Species composition varied with reef size, although reefs greater than 25 cm width exhibited relatively little variation. In comparison with other biogenic polychaete habitats, S. vermicularis reefs appear to support a highly diverse community, which exhibits a high degree of similarity with that found in association with aggregations of the horse mussel, Modiolus modiolus. The presence of the Connemara clingfish, Lepadogaster candollei, rarely recorded at such a northerly latitude, on several reefs, indicates that the reef habitat may provide a stronghold for this species at the edge of its biogeographical range.

The Macaronesian Islands in the mid-Atlantic pose a number of questions relating to their colonization by littoral tanaidaceans, as these taxa have no obligate dispersive phase. Recent surveys of the four main archipelagos discovered twelve species of tanaidacean, four of which are new to science, in seven genera (one new to science). In addition, some taxa described by Vanhöffen at the beginning of the last century were rediscovered. All the taxa are described, and their zoogeography, likely origin, and possible means of colonization are discussed.

In April 2006 and May 2007 abundance data of small coral colonies were collected in the central atolls of the Maldives (N3°35.9–4°26.6 E72°47.3–73°57.5) in order to evaluate variability in hard coral recruitment and post-settlement success. Visual quadrats were randomly placed in two reef typologies (oceanic reef and lagoonal reef) at three different depths. Colonies were conventionally defined as ‘recruits’ when smaller than 5 cm in diameter, whereas the term ‘juveniles’ was reserved for colonies ranging between 5 and 15 cm. Clear differences in the relative importance of the two size-classes across the three different depths and the two reef typologies were found. A size-structure index (SsI%), based on abundance data, was calculated in order to evaluate the percentage of ‘recruits’ out of the total juvenile hard corals. SsI% values differed between reef typologies and according to depth zones with a higher percentage of ‘recruits’ found in shallow oceanic reefs. Physical and ecological differences between the two reef typologies according to depth are presumed to cause different success in the settlement of new colonies and their survival during growth. Coupled with the usual estimates of hard coral cover, SsI% may represent a useful tool for monitoring, and be effective for the quick assessment of coral reef recovery after disturbances.

We document patterns of distribution and relative abundance of marine megavertebrate fauna around Cornwall and the Isles of Scilly from a combination of aerial and boat-based surveying. Between January 2006 and November 2007, 20 aerial surveys were undertaken, comprising over 40 hours of on-effort flying time. In April to October of these years, 27 effort-corrected ferry surveys were also conducted from a passenger ferry travelling between Cornwall and the Isles of Scilly. Opportunistic sightings were also logged by the crew members of the ferry and another vessel travelling regularly along the same route on 155 days. Ten megavertebrate species were sighted: basking sharks Cetorhinus maximus, sunfish Mola mola, common dolphins Delphinus delphis, harbour porpoise Phocoena phocoena, grey seals Halichoerus grypus, Risso's dolphins Grampus griseus, bottlenose dolphins Tursiops truncatus, minke whales Balaenoptera acutorostrata, long-finned pilot whales Globicephala melas and killer whale Orcinus orca. During aerial surveys, 206 sighting events of seven species were made, compared with 145 sighting events of eight species during ferry surveys and 293 sighting events of 10 species from opportunistic ship-board data collection efforts. Seasonal and spatial patterns in species occurrence were evident. Basking sharks were the most commonly-sighted species in the region and were relatively abundant throughout the estimated 5 km-wide strip of coastal waters covered by the aerial surveys, during spring and summer. Ferry surveys and opportunistic vessel-based sightings data confirmed that the distribution of surface-feeding aggregations of this species was largely around the coasts. Despite the limited scope of this study, it has provided valuable baseline data, and possible insights into the marine biodiversity of the region.

A line transect survey was conducted in July/August 1998 to investigate the distribution and abundance of cetaceans off north-west Scotland. Over 2156.5 km of survey effort, 304 sightings were recorded of which 184 were identified to species. Nine species were identified: Atlantic white-sided dolphin Lagenorhynchus acutus, fin whale Balaenoptera physalus, sei whale Balaenoptera borealis, long-finned pilot whale Globicephala melas, sperm whale Physeter macrocephalus, common dolphin Delphinus delphis, harbour porpoise Phocoena phocoena, white beaked dolphin Lagenorhynchus albirostris and Risso's dolphin Grampus griseus. The Atlantic white-sided dolphin was the most relatively abundant species. The relative abundance of large whales and dolphins was greatest in the Faroe–Shetland Channel. The continental slopes of this area are undergoing development by oil industries and concerns have been raised about the potential impacts of these activities on cetaceans. These waters are used year-round by cetaceans and provide feeding and breeding grounds and are a migration route for large whales.

The small hermit crabs of the genus Clibanarius are mainly found in tropical regions but one of them, C. erythropus (Latrielle), is common along Mediterranean shores (Holthuis & Gottlieb, 1958); this species was formerly known as C. misanthropus (Risso), but the name C. erythropus has priority (Forest, 1958) and is now in general use. Outside the Mediterranean the species ranges from Brittany to southern Morocco and the Azores (Holthuis & Gottlieb, 1958; Zariquiey Alvarez, 1968). In 1955–7 the extreme northern limit in Brittany was placed at Melon, between Brest and Trémazan (Crisp & Fischer-Piette, 1959); these workers, and also Carlisle & Tregenza (1961), were apparently unaware that the crab had been discovered at Roscoff, on the north coast of Brittany in 1955 (Rullier, 1959; Thiriot, 1965; Bourdon, 1965).

The present study aimed at estimating the characteristics of the Ascophyllum nodosum stands along the coast of Brittany, France. Although both an ecologically and economically important macroalga on sheltered rocky shores of the North Atlantic, no study has simultaneously dealt with the variability of the densities, lengths and biomasses of A. nodosum together with a description of its associated algal and animal diversity. There were significant differences in mean lengths and variations in the length–population structures between sites. However, the biomasses and densities showed no significant differences. The biomasses are amongst the highest ones estimated over the entire species distribution. The algal and animal assemblages were typical of A. nodosum zones, but only the identity composition of the algal communities seemed to reflect site differences in environmental forces. The biomasses measured in the present study should help improve future macroalgae biomass and metabolism estimates on regional or global scales. Finally, the data will provide a reference state for future studies on the responses of fucoid canopies to environmental changes.

Perinereis nuntia brevicirrus (Grube 1857), collected from a rocky shore at Qingdao (China) were cultured under different temperature, daylength and moonlight regimes. Ripe individuals were found in the field after an increase of water temperature in early summer, with a semilunar spawning peak from the beginning of June to the end of September. In laboratory experiments, daylength has no influence on maturation and reproduction. Temperature-controlled culture produces gravid, reproducing specimens at any time of the year after an increase in water temperature. For reproduction both sexual partners leave their burrows and swarm at the water surface in the early morning, performing a nuptial dance. The spawning behaviour, the nuptial dance and the release of gametes, are controlled by sex pheromones which are present in the coelomic fluid of mature worms. A sex pheromone from Platynereis dumerilü, 5-methyl-3-heptanone, is found in Perinereis nuntia brevicirrus and causes an increase in swimming activity during reproduction and the release of a small amount of sperm from males. This signal induces the release of eggs by the females followed by the release of masses of sperm by the male due to a second female pheromone.

Trypsin-like enzyme activity of the larvae of two planktonic predatory crustaceans, Homarus gammarus and Nephrops norvegicus (Decapoda: Nephropidae) and the omnivorous larvae of Carcinus maenas (Decapoda: Brachyura) were investigated at each larval stage until metamorphosis. Two copepods, herbivorous or omnivorous grazers, Centropages typicus and Temora longicornis (Copepoda: Calanoidae) were also investigated for this enzyme. A comparison of trypsin-like activity in these and other decapod larvae shows a pattern with high levels in herbivores, low levels in carnivores and intermediate levels in omnivores. Herbivorous planktonic crustaceans appear to rely on high digestive enzyme activities to extract nutrients from less digestible algae or particulates, whereas carnivorous larvae have limited enzymatic capacity as they feed at higher trophic levels upon large and easily digestible prey. Omnivorous Carcinus maenas larvae have intermediate levels of digestive enzymes and are able to transfer between herbivorous and omnivorous feeding.